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CreatePerspectiveMap_Points


Creates a perspective transform map from four points denoting a rectangle in the world coordinates.

Name Type Description
inImageFormat ImageFormat
inRoi Region* Range of pixels to be processed
inImagePoints Point2DArray Points define real object plane corners.
inTargetPoints Point2DArray* Points define target plane corners. If NIL then image corners are used starting from (0,0) (Width, 0) (Width, Height), (0, Height)
inNewSize Size* New image size after remapping
inInterpolationMethod InterpolationMethod Interpolation method used in extraction of image pixel values
outSpatialMap SpatialMap Created SpatialMap with perspective transform
outTransformMatrix Matrix Used transform matrix

Applications

Data preprocessing for fast perspective correction. The result is used by RemapImage.

Examples

Image before and after the perspective transform created by CreatePerspectiveMap_Path.

Remarks

This filter is a good choice for local perspective distortion removal - such as "unwrapping" boxes, as is depicted by the example above. Applications concerned with observing real-world flat surfaces (such as observing conveyor belts) should use methods that are more accurate. Please refer to: Machine Vision Guide - Camera Calibration and World Coordinates

Notice that both inImagePoints array and inTargetPoints must be made of four points. This filter creates point to point transform so changing the points' order in the array may yield an unexpected result.

The best way to understand the relation between inImagePoints and inTargetPoints is to present the first of them on the input image and the second on the background of the remapped image.

The image before remapping on the left (with inImagePoints) and the image after on the right (with inTargetPoints) created by CreatePerspectiveMap_Path.

Errors

This filter can throw an exception to report error. Read how to deal with errors in Error Handling.

List of possible exceptions:

Error type Description
DomainError Each of input array must contain four points in CreatePerspectiveMap_Points.

Complexity Level

This filter is available on Basic Complexity Level.

Filter Group

This filter is member of CreatePerspectiveMap filter group.

See Also

  • RemapImage – Applies a precomputed image transform, defined by a spatial map object.